YANKEE DISTRICT OF THE AMERICAN ROSE SOCIETY
Going Against the Grain
Growing & Winterizing Tree Roses in Northern Zones
By John Shelly
I live in South County, RI and grow and care for about 300 roses, mostly hybrid teas (HT), of which about twenty-five are standard 36-inch hybrid tea tree roses (TR). I have never lost a tree rose yet through one of our unpredictable winters because of a special winterizing technique that I have perfected. Although tree roses are very popular in the warmer climates, most people are afraid to grow them in Zones 4 to 6. If the price of buying a standard 36-inch tree rose (which is anywhere from $40. to $80.) is not enough to defer you from purchasing it, surely the recommended procedure of winterizing a tree rose in the northern zones will send you packing.
The recommended procedure consists of digging a six foot trench alongside the tree rose and bending it into the ditch, leaving half the root system intact and then pegging it down and finally mounding it over with a one to two foot layer of mulch and soil. I don’t think anybody relishes the thought of doing this every fall and, in my opinion, it is not necessary . . . unless you’ve always had a secret desire to become a ditch digger.
The other unnecessary recommended procedure is to dig up the tree roses each fall, put them in twenty-gallon pots and winter them over in your cellar or garage. This sounds like a real fun procedure, too. I can assure you tree roses do not like to be half-uprooted or dug up every fall. No rose does!
My procedure has had a hundred percent success rate and my tree roses have come through the severest hot/cold winters with very minimal dieback. They are strong, healthy plants that fare better than even the traditional winterized rose bush. This past winter was the true testament to my method, where we had temperatures into the low sixties and then several weeks of cold with minus twenty-degree wind chills. This is probably the worst scenario for rose survival. Although my rose bushes suffered a large amount of winterkill and dieback, my tree roses still have good eighteen-inch canes.
What is a Tree Rose?
A tree rose is any variety of rose grafted on a long trunk, usually a two to three year old ‘Dr. Huey’ root- stock with three to five bud grafts, instead of the usual one. They are typically available in four sizes: 18-inch miniature TR, 24-inch patio TR, and a 36-inch or 48-inch standard TR. I prefer the 36- inch standard TR.
Although many TRs are bud grafted directly onto long ‘Dr. Huey’ rootstock, some have an intermediate rootstock grafted onto ‘Dr. Huey.’ The bud graft is made on top of this thornless trunk. Rose varieties are somewhat limited due to the time and expense of producing a tree rose. Most distributors offer a two-year-old TR, but some distributors offer a three-year-old TR.
Choosing & Buying a Tree Rose
When buying a 36” standard TR, my choice in a tree rose, look at the trunk of the TR first. It should be as thick as possible, 3/4” to 1” in diameter: the thicker the better. Examine the trunk for holes and breaks. There should be a minimum of four good canes. Six canes are great! The canes should be in a somewhat circular pattern to give a nice rounded effect. Although nice, this effect is not critical. It’s more important to have four to six good healthy canes. The tree can be made round by directional pruning techniques.
Oh, did I forget to mention, as with buying any rose, don’t buy from a five-and-ten-cent store (if you know what I mean). I could never understand how roses get a good root system in a tiny tube-shaped piece of cardboard. Buy roses from a reputable rose nursery, preferably potted up in a large container. This is true for any rose. Always start off with a good, healthy plant. It will probably be the cheapest expense when planting roses. The soil amendments for the hole, sprays and fertilizer will cost more than trying to save a few bucks buying a rose from a discount store. Don’t get cheap on me now! You’ll pay the piper later if you do!
Now you have to make a decision on your rose variety. Many of my TRs are exhibition quality hybrid teas such as ‘Moonstone’, ‘Double ‘Delight’ and ‘Peace’. I chose these varieties because I enjoy showing roses. Many of these make good garden varieties and excellent tree roses, but not all. If you are not looking to compete on the show table, you may want to stick with floribundas because they produce more blooms, are fuller trees, and are usually more disease resistant. It is my opinion, and that of some distributors, that some varieties make better TRs than others, hence the limited availability of varieties. I will give you an example. I have a ‘Barbara Bush’ TR. Like a lot of others, such as ‘Peace’ and ‘Mr. Lincoln’, it tends to put out very long, thick canes which make for an odd looking tree. If you were to come to my house in the middle of June you would see this tree with its three-quarter inch trunk and huge canes extending up into the air to a height of eight feet. or better. A stepladder is needed to examine its beautiful blooms. At the other end of the spectrum, the ‘Bill Warriner’ tree rose has a nice compact, rounded form with tons of small coral blooms. You have to picture your rose variety selection growing about forty inches off the ground. Hybrid tea rose varieties with a medium growth habit such as ‘Double Delight’, ‘Moonstone’ and ‘Elizabeth Taylor’ seem to make the best choices. Forty-eight inch rose trees are available but are too high for hybrid teas. These should be bought for varieties such as the Fairy rose or some of the small Meilland varieties that have a weeping and flowing effect. The choice is yours.
Some of my personal picks are:
‘Double Delight’: exhibition and garden, nice rounded pattern, best of both worlds, minus the powdery mildew, live with the mildew (its worth it);
‘Moonstone’: exhibition and garden, great as a tree; best rose to come along since ‘Mr. Lincoln’;
‘Bill Warriner’: the very best garden rose, no disease, beautifully rounded, almost always in bloom, never without twenty to thirty blooms. Bill Warriner, the chief hybridizer for Jackson & Perkins for many years, knew what he was doing when he named this rose after himself. (Everyone loves it to death, especially in a tree!);
‘Spice Twice’: grows great as a TR. May not get to the show table because it lacks a high center, prone to bent neck but is a beautiful bright orange garden rose;
‘Betty Boop’: loves cool areas of the yard to bring out the deep red color, does great as a tree rose, has less of a black spot problem as a tree rose because of its height above the ground and better air circulation. (Plant two ‘Betty Boop’ bushes on each side of the TR and you have a real vibrant eye stopper.);
‘Gemini’: looks good so far, plant in a hot spot if you want the deeper red color.
Getting your Tree Rose Home and Planting It
One problem you might have after buying your TR is trying to get it home in one piece. They tend to be big, awkward and don’t fit very well on the front seat of your car. First of all, never pick up the TR by its trunk. Always carry it by the pot. The best way I found to get it home, is to fill the top of the pot with crumpled newspapers and tape them down with electrical or masking tape. Make sure the tape is tight to keep pressure on the soil; otherwise, the soil in the pot will end up on the floor of your car or truck. I also found it helpful to wrap the top with newspaper or waxed paper to prevent cane breakage. Using this technique, you can usually squeeze it into the passenger’s seat unless you have a volkswagon. If you transport it in an open vehicle, always keep the pot toward the front of the vehicle so the passing wind doesn’t break the canes.
After you get it home, dig the almighty hole. The best way is with a giant backhoe and a couple of construction workers. Don’t worry, just kidding. You can do it yourself with a shovel. It is very important that the tree be staked securely. The stake that is in the pot (usually a bamboo cane of some sort) will not do for support in your garden. It must be replaced with a better stake. I prefer a four foot, green metal fence stake. You know the kind, the one with the flat metal tab on the bottom. Drive this into the ground about six inches away from the trunk. Drive it in so the top of the stake is about three inches below the bud union. Take a wooden stake and fasten it on to the metal stake. The metal stake has holes so the wooden stake can be screwed to it. Secure the tree to the stake in two spots using two lengths of old garden hose that is rigid but still pliable. Plug the holes in the garden hose so insects can’t hide in it. It is preferable to put the stake on the south-facing side of the tree because this will give the trunk some protection from the baking sun in July and August. The trunk of the TR is susceptible to sun burn. Sometimes, during an extremely hot summer, it is best to wrap the trunk in burlap. This will help to keep the trunk from getting sunburned, keep it cool and minimize water loss. Spray the burlap on the trunk with insecticide; otherwise the insects will invade it.
After planting the TR I like to enclose a two-foot circle around the base of the tree using plastic lawn edging. I do this because I believe that it helps concentrate the food and especially the water in the root system. I water my TR about twice as much as a regular rose bush. I feel that the water has to travel a longer distance, and is more susceptible to water evaporation. Basically, I give them twice as much water as I give my rose bushes.
Unlike most rosarians, I continue to feed and water my roses right up until September although the recommended procedure says to stop feeding your roses approximately six weeks before the first frost in an attempt to properly harden off the canes and stop any new shoots that will fall victim to a deep frost. I believe it is more important to have a strong and healthy rose, particularly the root system, to ensure the rose’s survival through the winter. I also believe that as long as the soil temperature remains above fifty-degrees the rose’s root system will continue to feed and grow and become stronger to withstand the winter elements. In a mild winter they will continue to feed, sometimes into early December. The only thing that I do to help harden off the canes and concentrate on the root system is to remove the leaves in November.
Have you ever pruned a rose down to about three inches from the bud union (a real scary looking rose that you held little hope for) then watched it put out an abundance of basal breaks and grow like wild fire? I believe this takes place because of a really strong, healthy root system that has been fed for eight months rather than five.
Things You’ll Need to Winterize:
1. A good dormant oil. I prefer Ultra-fine spray, which is a paraffin-based dormant and seasonal spray.
2. One bale of salt marsh hay usually available at Agway or other farm product stores; cost $12.00 a bale, usually imported from Canada.
3. Insulated pipe wrap tubing available from places like Home Depot and other hardware stores. I use 3/4” I.D by 3/8” thick. It comes in 8 ft. lengths, split down the middle at a cost of about a $1.00 for an 8 ft. section. No need to tie it. There is an adhesive stick on the slit. Just place it on the trunk and squeeze it together; real simple and easy.
4. Bubble wrap, available at Wal-Mart and other places. It usually comes in 18” by 9 ft. rolls at a cost of about $2.00 a roll. Does about six trees. You know what bubble wrap is; it’s that stuff that comes in a box wrapped around breakable items. If you have any extra when you finish with the roses, you can bring it in the house and sit around and pop til’ you drop! It’s fun!
5. Burlap comes in 3 ft. by 25 ft. rolls. Cost about $4.00 a roll. Does about six trees.
6. Electrical tape.
The Shelly Technique
The weekend after Thanksgiving cut all remaining foliage from the rose trees. Don’t strip it off. Cut it off with shears. Do light priming. If possible leave about two feet of growth. Seal the larger cuts with a pruning stick. Spray thoroughly with Ultra-fine oil. Use the dormant oil concentration, which is usually about five teaspoons per gallon of water. Make sure to spray the trunk, bud union, canes and the ground thoroughly. Seal any open holes or cracks in the bud union or trunk with grafters’ wax. This eliminates hiding places for insects in the spring. When adding your salt marsh hay and burlap, spray it well in the process. It is very important to do this because it will deter and eliminate insects and spores trying to winter over on the bush.
Place the pipe wrap around the trunk, from the ground all the way up, overlapping as much of the bud union as possible. Remove the protective adhesive tape from the slit in the tube. Close the pipe wrap securely; it will stick together. Mound up mulch and soil about a foot up the rootstock. Fill the inside of the bush with loosely packed salt marsh hay. Wrap the bubble wrap around the bud union and the canes, starting at about four inches below the bud union, wrapping up about a foot. The bubble wrap will stick to the thorns on the cane. Don’t put any bubble wrap over the top of the bubble wrap cone. Position the salt marsh hay around the outside of the bubble wrap and wrap it with burlap. This process is easier if someone helps you hold the salt marsh hay as you wrap with the burlap. Make a couple of wraps around with burlap, leaving the top open with about eight to twelve inches of canes exposed. The burlap can be held and secured with electrical tape. With the top open you can fill in any voids using the salt marsh hay. Try not to pack it too tight. You want it light and fluffy but not stuffy! I like to leave the top somewhat open to allow rain and snow to pass through. It will also deter field mice from making a tree rose home. To summarize, the process consists of the pipe wrap insulator on the trunk, then starting from the outside of the bush the layers are burlap, salt marsh hay, bubble wrap and salt marsh hay in the middle. It’s a simple process that takes about ten minutes for each tree. Don’t ask me how or why it works. Not only does it work, but it works very well. I use this technique on some of my less hardy hybrid teas. When done, give the whole scarecrow one more good shot of spray and say good-bye to it until spring. I usually say these words, “Live long and prosper.” If you’re nutty enough to do all this, you probably talk to your roses, too!
Be sure your tree is securely staked. It may be necessary to use two stakes during the winter. These big scarecrows can get quite heavy in a heavy snowfall. I also do a very light pruning on the tree roses in the fall, letting them draw as much energy from the canes as possible. I believe my technique can be used on traditional rose bushes including tender hybrid teas in Zone 4 where rose lovers sometimes treat roses as annuals, having to purchase new plants every year because of winterkill. I might suggest you try my method, adding insulated pipe wrap on the canes. Good Luck!
Why Buy A Tree Rose?
I can’t say enough about tree roses. I don’t think any rose garden is complete without a few TRs. Some tree roses spread out here and there in a flat rose garden makes all the difference in the world. It adds height, contrast and a landscaped effect to what can be a somewhat dull, flat area. Many rose gardens contain trellises and arbors with climbers and ramblers extending up to add some height and contrast to the rose garden. These are all well and good, but these climbers and ramblers take many years to establish. A rose tree will add height and interest to your garden immediately. Another great plus about rose trees is that some varieties that are highly susceptible to blackspot, other diseases and pests, become less susceptible simply because the bush is four feet off the ground. This distances it from the lurking enemies down below. Furthermore the rose tree tends to have more air circulation because of its height. Also consider the advantage for pruning, spraying and inspection. It becomes more efficient because the rose is at eye height. This is better than crawling around on your knees in the mud and thorns. Above all else, there is nothing more beautiful than looking at a gorgeous standard hybrid tea rose tree at eye level and smelling its beautiful fragrance.
Author’s Acknowledgement: I’d like to acknowledge the help of my wife Lorraine and my daughter Crystal in helping me write this article.
Editor’s Note: This article received an Award of Merit from the American Rose Society. It appeared in two installments in the May 2000 and August 2000 issues of the Rhode Island Rose Review.
©Copyright 2009, all rights reserved. Yankee District of the American Rose Society & Patham